Resumen:
Annealing after cold rolling brings about the activation of recovery and recrystallization in microalloyed steels. The importance of recovery has been most often associated with its effects on the recrystallization kinetics. However, recovery has gained particular importance as an alternative heat treatment under the name "back annealing" or "recovery annealing". In the present work, various annealing treatments were applied to a Nbmicroalloyed steel in the range of temperatures and times where recrystallization is not complete. As a consequence, a large set of tensile strength-ductility pairs was obtained, even for conditions in which recrystallization was avoided. Through non-destructive magnetic coercive field measurements, recovery and partial recrystallization were monitored for each annealing treatment. Magnetic softening is significantly greater than mechanical softening. The variation in recovery in terms of temperature and time is highly affected by the presence of Nb in solution in the hot band (before cold rolling). At low recovery annealing temperatures, 350-450 degrees C, Nb solute drag on dislocations is the main mechanism that controls recovery, whereas at 550 degrees C, Nb strain induced precipitation leads to a recovery plateau in terms of coercive field.
